Cardiac arrhythmias may lead to heart disease and death. Arrhythmias may be treated by medication, implantable devices, or by the ablation of specific heart tissue found to be causing arrhythmia. Ablation may be performed by a number of techniques, including the local application of energy, for example, radio frequency energy, or by the application of cryogenic temperatures to the site of the problem tissue.
The specific heart tissue responsible for arrhythmia in a patient may be identified by moving a mapping catheter having one or more electrodes around the interior of the heart and measuring cardiac signals to sense changes in the electrical fields. A map of the electrical conductivity of the heart may be formed from the measurements to identify abnormalities which may be candidates for ablation. Some mapping catheters are designed such that the electrodes may physically contact the heart wall, including flexible designs that are inserted in a compact form and later deployed into a basket-like array. Such an array is deployed after entrance into the heart, and undeployed upon completion of the mapping and prior to removal from the heart.
During the mapping procedure, it may be beneficial to flush the array with an irrigation fluid, such as a saline solution, to reduce the formation of blood clots on the array. The saline solution may include an anticoagulant, such as heparin, to further reduce clot formation.